It is a Greek suffix which means gathering, contraction, shrink, shrink action. It is a phenomenon of a tissue affected by a decrease in temperature (heat) or light. The fotonastia is the property have some flowers open to feel the heat of the Sun and then close itself off from its concealment.
Nastia: Greek adjective nastos, tight. Normally contractile and adirectional reaction of plants to external stimuli such as light ( fotonastia ) , temperature ( termonastia ) , severity ( geonastia ) or movements ( sismonastia or thigmonasty ). The sismonastias of some sundews are curious to catch the movement of some insect or the mimosa pudica leaves to be touched.
